This invention relates to an emergency escape system which permits a rapid but safe exit from high-rise structures. The system is particularly suited for a rapid escape from a burning building where access to stairs is blocked by smoke or flame.
The need for a safe and effective system, especially one that does not rely upon the physical prowess or strength of the party seeking to escape a burning building, has been recognized for many years. As larger buildings are constructed, often with less than adequate means to escape from the uppermost floors thereof, the need becomes more acute.
U.S. Pat. No. 3,826,341 to Ledner describes an emergency descent device which includes a houring containing a tortuous path through which a vertically extending strand is drawn as the housing moves downwardly along the strand. An automatic braking mechanism, acting upon such strand, is included in the housing and is deactivated by the user to control the movement of the housing down the strand.
Similar and perhaps less complex devices have been known for years. Certain of these early devices and the problems associated therewith are described by Ledner in his patent in this manner.
1. U.S. Pat. No. 300,090 to Larson et al. shows a device in which a strand of rope is directed through a tortuous path housing and the rate of descent along such rope is controlled by cam levers which may be actuated by the escaping party or by someone on the ground, or by someone in an adjacent building.
2. U.S. Pat. No. 722,713 to Johnson shows another device which permits the operator to descent along a strand while controlling his speed with a pair or rope gripping jaws.
3. U.S. Pat. No. 812,950 to Price shows yet another tortuous path escape device with a friction brake which permits control of the speed in only one direction along the strand.
4. U.S. Pat. No. 933,685 to Wray illustrates an escape system which permits movement in either direction along the strand and includes separate friction brakes for control of movement in the opposing directions.
5. U.S. Pat. No. 1,059,754 to Paquet depicts yet another toruous path fire escape in which the strand is directed along a helical path through the housing and may be engaged by the operator with hand operated friction brakes which control the rate of descent in either direction.
6. U.S. Pat. No. 1,497,534 to Bass shows an escape device in which the strand is led around a friction roller and past hand actuated brake devices at either end of the housing.
7. U.S. Pat. No. 2,544,694 to Phelan discloses a fire escape apparatus in which the strand is directed around a stationary sheave, through a pair of braking devices for controlling the rate of movement in one direction along the strand.
8. U.S. Pat. No. 3,674,116 to Vogeli teaches a fall-prevention device from a fixed structure rather than a controlled movement escape system. However, the patent illustrates an interesting concept of a device which operates in conjunction with a fixed path in the form of a C-shaped channel member. A slide member, to which a person may attach himself, is locked against movement by a cam which causes the slide member to grip the channel member.
Various problems are associated with each of the above devices. For example, a person using such devices is required to actuate the devices using levers separate from the grips on which such person would normally steady himself during his descent. Also, the effectiveness of the speed controls in many instances depends upon the strength of the person who applies the control. Many of such devices have the obvious disadvantages of requiring a conscious person, and in many cases a strong and/or heavy one. However, in a situation where the escaping person is unconscious, elderly or a frightened infant, such prior art devices are ineffective.
Finally, a major disadvantage of many of the devices is the inability to readily reuse the escape or descent system. The present invention recognizes the need to provide a safe and effective means of escape for all parties irrespective of their physical state or age. Such means will become apparent from the specification which follows.